1. Field of the Invention
The present invention relates to a printing system wherein image data for printing is sent from a computer to a printer so that the printer performs printing based on the image data received from the computer.
2. Description of the Related Art
For controlling an operation of a printer, a computer stores a printer driver which is executed on an operating system of the computer. The printer driver is software for converting image data produced by an application executed on the operating system of the computer into a printer language. There have been available printer drivers for a page description language (PDL) emulation and a host base printer (HBP) emulation. For the PDL emulation, bit-mapping of image data is carried out in a printer. On the other hand, for the HBP emulation, bit-mapping of image data is carried out in a computer.
The printer driver for the PDL emulation converts image data from the application into a page description language and sends the converted image data and command sets to the printer. In response, a controller of the printer converts the received image data into an intermediate data format of a display list, and then converts it into bit-mapped image data matching with the print resolution of the printer.
In the PDL emulation, the printer starts printing after receipt of one-page image data. Accordingly, a processing load of the printer driver itself is small for the PDL emulation. Further, the data transfer amount from the computer to the printer is small as compared with the HBP emulation so that the high data transfer rate is not required. On the other hand, the data processing capability required to the controller of the printer is high.
The printer driver for the HBP emulation converts image data into bit-mapped image data matching with the print resolution of the printer, and then compresses the bit-mapped image data for sending to the printer. In response, the printer expands the compressed bit-mapped image data for printing.
In the HBP emulation, the printer starts printing before finishing receipt of one-page image data. Specifically, the printing is implemented in parallel with receiving the image data. Accordingly, a processing load of the printer driver is quite large for the HBP emulation. Further, the data transfer amount from the computer to the printer is large as compared with the PDL emulation so that the high data transfer rate is required to follow the printing speed of the printer.
The foregoing conventional techniques have the following problem.
Owing to the remarkable advancement in processing capability of personal computers and the reduction in price thereof, it becomes relatively easy to achieve a high throughput required for the HBP emulation. Under the circumstances, there have appeared multi-emulation printers which can support both the PDL emulation and the HBP emulation. For effectively utilizing these printers, it is necessary to properly select a printer driver depending on various printing conditions, i.e. environments of the computers and the printers.
For this purpose, JP-A-7-162722 discloses a technique wherein a computer receives a status signal from a printer and selects a printer driver based on information contained in the received status signal. However, the optimum printer driver changes depending on various printing conditions and thus it is practically difficult to select the optimum printer driver. Accordingly, more concrete and practical techniques for automatic printer driver selection have been demanded.